What word is used to describe the dilated trigones of the lateral ventricles?
Colpocephaly.
To what object are the lateral ventricle likened to when imaged axially?
A racing car (viewed from the top).
What happens to the white matter tracts which normal would cross in the midline via the corpus callosum?
They are oriented vertically, separating the lateral ventricles widely (accounting for the racing car configuration). These bundles of white matter are known as Probst bundles.
MRI of the brain demonstrates absence of the corpus callosum with the interhemispheric sulci reaching the roof of the third ventricle. The ventricles are widely spaced with prominence of the trigones (colpocephaly). When imaged axially they have a racing car configuration.